[sdiy] line to cv amplifier schematic

[Seb Francis]

tuj wrote:

> Does anyone know where I can find a simple schematic for a circuit that
> will take a line level input and amplify it to a 10v signal?

A single opamp and 2 resistors should do the trick I think

connect line level signal to opamp + input
connect opamp - input to ground via R1
connect opamp - input to opamp output via R2
take signal output from opamp output

gain=(R1+R2)/R1

there's a pic here (3rd pic from the top):
http://www.symanski.net/electronics/opamp.html


If you have a 150mV p-t-p line signal, you need a gain of about 67, so R1=1K, R2=66K (or near to this)

For the opamp, I recommend NE5532, running off +-15V (or +-12V is ok)

For short-circuit protection (recommended if the output goes to a jack socket), stick a 100R resistor between opamp output and R2/signal output

Seb